Chronoing grenades??

Decoy

Apologies in advance if this contravenes the section of the charter that states we are not allowed to discuss airsoft devices >1joule. I am not stating that any device mentioned here is >1j, I am only asking a question. I'm not looking to start another debate on our 1joule limit, I for one am perfectly happy to abide by the law as should every right-minded airsofter. What I'm hoping for here is some objective, informed comment from those with the required knowledge in the necessary areas - physics, ballistics, etc.


Statement
I have seen several statements since I started airsofting that CO2-powered grenades, both frag & moscart (M203?) can be >1joule. If this statement is correct how are they allowed in common usage on Irish airsoft sites?

Question
Am I correct in saying that the 1joule limit laid down in the relevant legislation refers specifically to the muzzle energy of an airsoft device? If yes, how can the muzzle energy of a non-directional airsoft device such as a Thunder-B be measured?

Question
In a similar vein, can an M203 actually be chrono'd? How would any chrono allow for multiple BBs being simultaneously ejected from the grenade?

Leftyflip

Volume of the gas, pressure of the gas, rate of expansion of gas, amount of volume the gas must take up, weight of projectile. I'm probably wrong, physics isn't my best subject.

Mind you a high speed camera would do it just aswell...

Puding

As lefty said the only way reliably to test shower m203 is with high speed photography , thunder b do not have a barrel so the 1j rule is not applicable

Inari

As far as I am aware, the legislation is not specifically airsoft related. To the best of my knowledge it is written in legalese, which makes it open to interpretation (however, in order to interpret it you need to be a qualified solicitor etc...I think) if it ever came to court. Basically it is "any projectile fired from a barrel at a muzzle velocity of greater than 1 joule of energy, is considered an illegal firearm" (quite clearly paraphrased, but I should make it double clear).

In the case of an M203, the launcher is arguably the barrel. Now here is the fun part - since an M203 grenade fires multiple projectiles from the same firing mechanism, as opposed to the 3-barreled shotgun style. At the moment there is no legal precedent for dictating how the power limit is applied. For example, do you add the collective weight of all the BB's, and judge its power accordingly? Or, do you judge the power in relation to each individual BB? It's really anyone's guess.

The Thunder B with BBs loaded into it is a strange one. Technically it has no barrel, but the projectiles (according to tests done with a radar chronograph by Andy_g) come out at well over 1j, but is it illegal considering it has no barrel? Once again, there is an absence of any legal precedent.

It's all a bit...hazy, to be perfectly honest. Perhaps the IAA can shed some light onto the matter?

Decoy

Puding wrote:

thunder b do not have a barrel so the 1j rule is not applicable

As I suspected

Puding wrote:

As lefty said the only way reliably to test shower m203 is with high speed photography

So if it is thought that they may, in some cases, be >1joule, yet they can't be chrono'd in any practical way on site, how are they allowed?? No, I'm not trying to start a campaign to ban M203s, I use them myself and want to continue to do so, but the question of their legality deserves some attention.

Puding

I would make the argument the the m203 grenade itself actually has the barrels rather than the launcher, the laucher in airsoft has no effect on the projectiles ( unless your using the really old sun project m203 with 6 inbarrels that worked with the grenade, but I do not think that is made anymore)

Private Snafu

I wouldn't mind knowing the approximate power of shells either to be honest.
If anyone is contemplating testing them, I've most brands and types of them here and would gladly volunteer them for it

Inari

Puding wrote: »

I would make the argument the the m203 grenade itself actually has the barrels rather than the launcher, the laucher in airsoft has no effect on the projectiles ( unless your using the really old sun project m203 with 6 inbarrels that worked with the grenade, but I do not think that is made anymore)

Aye, I was thinking that after I wrote it. The launcher just facilitates the firing mechanism. Do you measure the power from each barrel, or as a whole? Each BB, each collective BB per barrel, or them all? It's a tough grey area, and unfortunately I don't think it's one Boards.ie can sort through discussion. I reckon it's literally a case of awaiting legal precedent (this seems to be turn-of-phrase of the day for me )

Decoy

In theory an M203 could be loaded with 1 BB and chrono'd that way but that would not be a fair test, even if that 1 BB tested >1joule that configuration was not the way the device was designed to function. Besides, I doubt a single BB would be >1j as the majority of the gas propellant would vent through the empty 'barrels'.

Puding

Decoy wrote: »

As I suspected




So if it is thought that they may, in some cases, be >1joule, yet they can't be chrono'd in any practical way on site, how are they allowed?? No, I'm not trying to start a campaign to ban M203s, I use them myself and want to continue to do so, but the question of their legality deserves some attention.

Depends a lot with co2 on how the charger is set up , the madbulls can take up to 800psi + .

In terms of staying legal I go with common sense, I know far a 1j aeg with hop up off will go, I use that distance as a yard stick , also you can use another garage chrono method and check penetration into somthing like mud 1j v m203

the reality is that it is a very grey area

Decoy

Puding wrote:

I know far a 1j aeg with hop up off will go, I use that distance as a yard stick

Interesting methodology, it's simple to implement & makes a lot of sense.

Puding

Inari wrote: »

Aye, I was thinking that after I wrote it. The launcher just facilitates the firing mechanism. Do you measure the power from each barrel, or as a whole? Each BB, each collective BB per barrel, or them all? It's a tough grey area, and unfortunately I don't think it's one Boards.ie can sort through discussion. I reckon it's literally a case of awaiting legal precedent (this seems to be turn-of-phrase of the day for me )

My understanding of the wording would mean you would need to test each barrel , a203 can have up to 8 barrel with a shared power source, the law mentions barrels so if a projectile leaves it, it needs to be a joule

Puding

Decoy wrote: »

Interesting methodology, it's simple to implement & makes a lot of sense.

The theory is sound if you remove hop up but you have so many factors in play I would not want to go to court with it

ronan keane

Sorry i don't know the name of the specific chronograph but I watched Future Weapons non-lethal special yesterday and the chrono they used for the rubber shotgun round could be used to chrono the thunder-bs and m203s in theory.

Decoy

ronan keane wrote: »

Sorry i don't know the name of the specific chronograph but I watched Future Weapons non-lethal special yesterday and the chrono they used for the rubber shotgun round could be used to chrono the thunder-bs and m203s in theory.

Two questions/issues with that.

I'm guessing the rubber round was more than likely a single baton-type round rather than multiple, smaller pellets as there are already alternative non-lethal shotgun munitions available and it would make little sense to develop another option. If this is the case the comparison is invalid.

What type of chrono did they use? I'm guessing it wasn't a Madbull or XCortech or even a SKAN, so do you think an Irish site will stump up the cash for a milspec chrono?

ronan keane

Im just saying if a rich scientist wanted to teat it they can do it and the chrono was like a square and when the projectile hits it its gives a reading

NakedDex

Decoy wrote: »

In theory an M203 could be loaded with 1 BB and chrono'd that way but that would not be a fair test, even if that 1 BB tested >1joule that configuration was not the way the device was designed to function. Besides, I doubt a single BB would be >1j as the majority of the gas propellant would vent through the empty 'barrels'.

The problem with doing that is you create a gas imbalance within the chambers, so any test using that method is void by it being inapplicable to actual-use values.
Gas, like any other fluid, will take the path of least resistance available to it. If your grenade has six chambers, five being empty and one having a blockage (the loaded round), you will find an increased volume of gas expelling from the empty chambers. This, in turn, will give you a lower volume venting through the chamber with the loaded round, resulting in a lower velocity shot.

Similarly, if you block all five other chambers (running with the hypothetical six chamber grenade test here) and load the sixth, you now have the entire tank venting through one chamber, dramatically increasing the velocity of the round expelled from such. Again, this would void the test.

Really, the only way to conduct a muzzle velocity test is using high speed cameras and a gradient board, loading the grenade as normal, but using one high contrast round of the same weight and values as all others in test (eg, using King Arms .2g black rounds with one King Arms .2g white round in a chamber as the measured round).


There are other things to take into account too. Gas systems are notoriously unreliable for chronoing. Simply holding the grenade for a minute before firing is enough to change all of your readings. Before testing could even be started, a suitable laboratory type condition would need to be set up, where a constant temperature, humidity and (crucially, though oft forgotten) atmospheric pressure can be controlled and measured.
Now, this may all seem like overkill, but if we're straying down the road of "are these legal or illegal" then you need to eliminate every variable before someone starts shouting about a large predatory canine approaching your flock of be-woollen charges.
If, however, this is merely a discussion hoping for anecdotal evidence of power limits, then there are other options. None of them thoroughly reliable, but probably as close as you'll come with organising a lot of equipment and white coats. For example, the theory route suggests you could simply work out the expected muzzle energy using gas laws and fluid dynamics. Take your gas density and pressure etc and plug them into formula along with some assumed variable numbers (eg, assume 20C at XX.XhPa atmospheric etc).
Alternatively you could range test on the day, with any grenade that can fire beyond a certain distance limit from a flat trajectory deemed to powerful.
You could also, if you know the right people, rent an impact accelerometer and simply fire each grenade at it. The problem with this is that it doesn't give muzzle energy so much as impact energy, which will be cumulative if more than one round strikes at the same time. It would, however, give you an indication of expected power which could be compared from one grenade to the next.

And therein lies another issue. Every single grenade is different. Not just from one brand or model to the next, but every individual grenade. Some release faster than others, which has a dramatic impact on performance. Others have differences in seal type and consistency, pressure ratings and tank capacities. Green gas is held in liquefied form, which also means the physical orientation of the grenade makes a difference to performance as well as possible leakage. Overfilling or underfilling are further inconsistencies the user bears, where dried seals or bad machining means a properly filled tank can slowly leak to a much lower pressure before being fired.



I could keep going with this. There's a hell of a lot to it. It's not just difficult because it fires a number of rounds at once, it's difficult because the propulsion system is completely unregulated and subject to any one of hundreds of variables from time of day to how strong your finger is.

The one thing I can say with absolute confidence is that foam/rubber/Nerf/rocket head rounds are illegal. Whatever about scattershot grenades using the chambers or the launcher as the barrel (that's a debate that could go on for a long time), these specialist rounds definitely use the launcher as a barrel, and their mass means they're well in excess of the limits, despite being totally harmless.

For what it's worth on the barrel debate, my vote goes toward the launcher being the barrel of question. My rationale for this is simply that, if you cease to view the system as a grenade launcher and grenade, which it only mimics in physical appearance and not in operation, you'll see it's far more similar to a shotgun/blunderbuss. These devices impart simple linear direction upon loosely fired objects by passing them down a widebore barrel. I'd consider this the closest equatable neighbour which could be used as a precedent for determination of type.

bullets

Ahhhh welcome to grey areas in Irish Law!
Anyone can interpret the laws and quote them and read into certain types
of wording and manipulate the interpretation of the wording due to context and arrive with completely different and opposite answers.
(but its how much you pay a good solicitor to prove your and their interpretation is what counts in court should you fall foul of the law )

When is a barrel not a barrel is what I gotta ask.
Chicken and the egg syndrome for Nades I reckon.

Law states projectile from a barrel.

Is the Grenade itself considered the ammunition "for" the Launcher
and the launcher being the device, or is it the BB's inside the Grenade considered the ammo and the grenade is the Launcher and device.

BB's go in grenade, grenade goes in launcher, The grenade does not get fired though, so it cant be the ammo or projectile since it does no get launched itself.

Is Launcher then irrelevant ? its it the grenade thats the 1j restriction.
or is it the launcher that holds the grenade that holds the bb's

Also are all arguments null and void if a single BB manages to get Chronoe'd at over 1j while flying through the air ?
regardless of if there was or was not a barrel surrounding at the time of firing it.


For These type of debates we should all be in the Pub together getting pissed out of our minds drunk
and having a good ol laugh around a table.

~B

NakedDex

Exactly, the whole debate is so mired in hearsay, opinion and conjecture that it'll likely never be ruled upon.

However, in the spirit of the state we live in, I'll back up my opinion on it based on what you pointed out regarding the grenade.

The law applies to a projectile leaving a barrel, and it's velocity as measured at the muzzle. Now, if you consider the 40mm grenade itself, it's actually not much more than a storage system. It holds ammo and propellant in a charged state ready to be fired. Similarly, a shotgun cartridge holds shot and propellant in a ready-to-fire state. The shotgun cartridge, however, has no controlled method of firing outside of the barrel and firing mech of the shotgun itself. The grenade shell also has no means of controlled firing outside of the launcher.
The operative word here is controlled. Either could be set off through "manual" misuse, but designed use requires a controlled firing through a barrel using a trigger controlled firing pin. Ergo, the launcher barrel is the barrel from which a muzzle velocity is taken as the projectiles haven't exited the controlled system until they have been expelled from the launcher.


This is more or less how I see it. Were the grenade to be mounted proud of the launcher, such as with the Madbull rifle grenade, then I would concede in that instance that the grenade's chamber is the barrel. The key, for me at least, to the argument is where the last point of directional control is with the system.

3102derek

just got to say this type of thread is what makes boards great. well done

Puding

NakedDex wrote: »

Exactly, the whole debate is so mired in hearsay, opinion and conjecture that it'll likely never be ruled upon.

snip

i can understand that logic and the normal thing to do is compare a m203 to the shotgun shell, the problem i see with this is that m203 performance is exactly the same in terms of power output be it in or out of the launcher, as you say it would only ever be resolved by a legal president and i do not think we want to go that far

NakedDex

You could argue a shotgun cartridge could be fired without the shotgun too. In or out of the breach, the cartridge will produce the same force, but in a less controlled manner.
It's the gun that has the firing mechanism to safely discharge the shot, it's also the gun that has the barrel down which the shot is discharged. I can accept that this might be a tad simplified as a reasoning, but it's the closest I can fathom to an answer, and it's the assumption under which I've operated them thus far.

Puding

agree you could of course fire the shotgun cartridge without the barrel, the difference i see is in performance, with a shotgun cartridge you will get difference performance in and out of the shotgun, with a m203 cartridge the performance is exactly the same in and out of the launcher

Firekitten

If the shell is considered ammunition, then it poses an interesting concept...

In the UK, items with over 12g barrel, are not covered under firearms law... not a section 5 firearm atleast. I think somehwere, it states blunderbusses and cannons are entirely legal...

What ive the 40mm part makes it a different kettle of fish?

(I only noted this because by such logic, m203 launchers, m79s etc are exempt from the VCRA restrictions (yum)

fayer

Decoy wrote: »

Apologies in advance if this contravenes the section of the charter that states we are not allowed to discuss airsoft devices >1joule. I am not stating that any device mentioned here is >1j, I am only asking a question. I'm not looking to start another debate on our 1joule limit, I for one am perfectly happy to abide by the law as should every right-minded airsofter. What I'm hoping for here is some objective, informed comment from those with the required knowledge in the necessary areas - physics, ballistics, etc.


Statement
I have seen several statements since I started airsofting that CO2-powered grenades, both frag & moscart (M203?) can be >1joule. If this statement is correct how are they allowed in common usage on Irish airsoft sites?

Question
Am I correct in saying that the 1joule limit laid down in the relevant legislation refers specifically to the muzzle energy of an airsoft device? If yes, how can the muzzle energy of a non-directional airsoft device such as a Thunder-B be measured?

Question
In a similar vein, can an M203 actually be chrono'd? How would any chrono allow for multiple BBs being simultaneously ejected from the grenade?

This question was raised by the lads in cork when I was part of the IAA, we took it to the DoJ and there response was, BB showers would be measured with only 1 BB in the device. How this could be achieved I do not know. We had much debate on the matter with them, they were very helpful, but the method was over to the firearms team in the Guards to design.

We also came across BB showers that were +1 Joule, no question form the department they are illegal. Personally I cannot see them doing major damage as the power is spread over a wide area, but the statement on the subject was clear and unequivocal.

Steve

F.U.B.A.R

ronan keane wrote: »

Im just saying if a rich scientist wanted to teat it they can do it and the chrono was like a square and when the projectile hits it its gives a reading

I think you are reffering to an impact plate which messures impact in G's to determin lethality ect but does not give a velocity messurement. However they did use a crono that would be similar to one found at a crossbow range and I would guess that could be used to determin the velocity of M203